Isaia dress shirts - different cuts?

[corhart]

I recently purchased two Isaia dress shirts on sale from Neiman Marcus size 16/41. I noticed that they fit much fuller and with longer sleeves than my other Isaia shirts of the same size. The strange thing was that the 15/40 was noticeably smaller, with shorter sleeves and just overall uncomfortable, so I figured that I was just imagining the difference on the 16/41. After I had the sleeves on the new shirts shortened, I noticed that under the size tags on the old shirts there is a smaller tag with the letter "I" while the new shirts had a smaller, hidden tag with the letter "E." The older shirts were purchased from a local men's store and not NM. Are there different cuts? Are some designed for NM with a different style?